Brake mechanism for electric elevators



(No Model.)

P. E. HERDMAN. BRAKE MECHANISM FOR ELECTRIC ELEVATORS.

No. 568,570. Patented Sept. 29, 1896.

Witnesses.

Inventor.

M g mm Attorney.

UNITED STATES PATENT OFFICE.

FRANK E. HERDMAN, OF WINNETKA, ILLINOIS.

BRAKE MECHANISM FOR ELECTRIC ELEVATORS.

SPECIFICATION forming part of Letters Patent No. 568,570, datedSeptember 29, 1896.

Application flled October 1895- To all whom it may concern:

Be it known that I, FRANK E. HERDMAN, a citizen of the United States,residin at Winnetka, county ofCook, and State 0 Illinois, have inventeda new and useful Improvement in Brake Mechanism for ElectricElevators,of which the following is a full, clear, and exactdescription, reference beinghad'to the accompanying drawing, which formsa part of this specification.

The brake used in my invention is a friction-brake, and, as is known,the time in making a stop with a frictional brake is proportional to thespeed and load. If the car he descending and the velocity or load isgreat, it takes more time to bring the mechanism to rest, while, on theother hand, if the velocity be less or the load light the stop is mademuch quicker. 'The purpose of this invention is to obviate this and tomake the ap-' plication of the brake varyas the conditions of speed andload vary, so as to make the stop constant.

I will first describe the construction as illustrated in the drawing andthen particularly point out the invention in the claims.

In the accompanying drawing the figure shows a diagram maticalview ofmy'invention.

E is an electric motor, of which e is its shaft.

200 is a reversing-switch controlling the admission and direction ofcurrent passing to 1 the motor. This switch 200 has the hubsa a a, whichhubs are all connected with the operating-shaft, but the hub a-isseparated from the hub a by the insulation a and the hub a is separatedfrom the hub a by insulation a the hub a being of conductive material.To the hub a are attached the brushes a and a, to the hub a, is attachedthe brush a, and toxthe hub a is attached the brush a. Above the brushesare contacts 100 88 87 97, and below said hub are contacts 99, 90, 89,and 98, brush on making contact with the contact 100 or 99, dependentupon the direction in which it is moved, the brush a with contacts 88 or90, the brush a with contacts 87 or 89, and the brush a with contacts 97or 98. The hub a is directly connected with one pole of the source ofcurrent supply by wire 80. The contacts 100 and 99 are directlyconnected with each other by wire, and con- Serial lie-564,735. (Nomodel.)

tacts 88 and 89 are cross-connected, and so are contacts 87 and 90, and97 and 98 are also connected together. The direction in which the switchis moved merely determines the direction in which the current passestothe motor, or rather to the armature. Otherwise no diiference is causedby the change of dircction of the throw of the switch.

The connection to the field of the motor is madein the following manner,supposing the switch to be moved so that the brushes come in contactwith the contacts 99, 90, 89, and 98: From cont-act 99 a wire passes tothe solenoid 101, having a contact 104 connected with its core, from thesolenoidlOl to one side of the field, from the other side of the fieldto the contact 98, from thence to the hrusha, and from the brush a tothe fieldresistance 96, thence through the arm 79 to a contact 300,which contact is connected with the controllingesolenoid 83, thence tothe other pole of the source of current supply. The current to thearmature passes from thr.v contact 90 directly to one pole of thearmature, from thence back to the contact. 89, thence to the brush (F,from brush a through wire 85, to the solenoid'74, (the purpose of whichwill hereinafter be described,) and from the solenoid 7 4, by wire 84,to the armature-resistance 8T0, thence, by means of the arm '79, to thecontact 300, thence through the solenoid 83 back to the opposite pole ofthe source of current supply. The movement of-the resistance-arm 79 iscontrolled by the solenoid 730, which is connecteddirectly with thecontact 100, and from the other end of the solenoid a wire passesthrough the contact 300, through the solenoid 83,120 the other pole ofsource of current supply. The purpose of the controlling-solenoid 83 andits operation are fully described and claimed in certain Letters Patentissued to me, said patent being dated December 11, 1894, and numbered530,773.

From the foregoing it may be seen that th solenoid 74 is directly inseries with the armature of the motor. The coreof this solenoid is asecond solenoid 73, to the core of which latter solenoid is attached therod 7 0, having upon it the weight 71. This rod 70 is a forked rbd andsurrounds the brake-lever Q of a friction brake-wheel Q upon themotor-shaft c. Between the weight 71 and the lever Q is placed acoil-spring 7 2.

q is a brake-band operated by the brakelever Q. The solenoid 73 on oneside is in direct electrical connection with the contact 300 and theother side in direct electrical connection with the contact 100. As aconsequence, when the switch 200 is operated, a circuit is completed tothis solenoid 73 independent of the armature-circuit, that is, it is inshunt with the motor. This solenoid 73 carries at the end opposite towhich the weight is attached an armature 75, which coacts with themagnet 76. This magnet 76 is connected to one pole of the source ofcurrent supply through a wire connected with contact 300, and isconnected to the other pole of the source of current supply by means ofa wire which is connected with the contact 94 on the switch 78. As shownat 77 in the drawing, this switch is controlled by the operating-bar P,and when the operating-bar is at its center the current is out off fromthis magnet 76, but when it is moved either to the right or leftconnection is made between contact 94 and either contact 93 or 92 andthus the circuit completed to this magnet. When the switch is operated,a circuit is made to the solenoid 73, which becomes energized, and itscore moves so as to lift the weight 71. The strength of this solenoid 73is just en ough-to release the weight 71 from the brake-lever Q. As thecurrent passes to the armature, and dependent upon the amount ofcurrentwhich the armature takes, the solenoid 74 becomes energized andproportionately lifts the brake.

Now let us take the application of the brake under varying conditions.If the elevator is ascending with a heavy load, itwill come t restitself veryquickly as soon as the current is cut oif the machine. Suchbeing the case it needs no assistance from the brake. On the other hand,if the elevator is ascending with the elevator properly loaded, and theoperator slows down, the brake is not applied, because the armature isconsuming a sufiicient amount of current to energize the magnet- 74sufliciently to hold the brakefree from the wheel. In consequence thebrake is not applied until the main circuit is entirely broken, and thiscan be as late as the operator may desire. On the other hand, if theoperator is ascending with a light load, the amount of current passingthrough the solenoid 741s little or nothing. As a result it will beenergized just enough to hold the brake off the wheel, and, when theoperator turns the bar to slow down, as the current is cut off from thearmature-circuit or resistance is thrown into it the strength of thesolenoid 74 will be decreased and the brake applied proportionately tothe decrease of its strength. It the load is over-counterbalanced, itwill require considerable brake to stop it. Under these conditions, whenthe current is cut oil from the motor it is turned into a dynamo andgenerates a current. of its own, which passes through the solenoid 74 inthe direction opposite to that in which the current passes through saidsolenoid from the source of current supply, and in consequence changesits polarity; but until the current is completely out off from themot-orit will pass through the solenoid 73 in a direction opposite tothat in which it passes through the solenoid 74 under these conditions,and as a consequence the action of the solenoid 74 will be to repulsethe solenoid 7 3, and as a consequence apply the brake with-considerablestrength.

The purpose of the magnet 76 is that under certain conditions wheremeans are provided to regulate the speed of the motor independent of thebrake, such, for instance, as electrical means, it is desirable toprevent the application of the brake until the current is completely cutoff from the motor, that is, until the operating-bar is broughtto acentral position. In this case the magnet 7 6 comes into play. Thismagnet is of such strength that it is not of itself sufficient to liftthe solenoid 73, but when the solenoid 73 has been lifted by thesolenoid 74, so that contact is made between the armature 75 and thearmature 76, it will hold it in such position until the current is cutoff. This current to the magnet 76 is controlled by means of the switch78 upon the operating-bar P, as before described, so that the brake isheld off until the bar P is brought to a central position. When it isbrou ght to this central position, the connection between the armature75 and the magnet 76 of course is broken, and as a consequence thesolenoid 73 is capable of moving so as to applythe brake, and it is somoved proportionately as the current in the armature-circuit isdecreased, thus decreasing the strength of the solenoid 74, or due tothe extent to which the solenoids 74 and 73 are energized in oppositedirections.

The purpose of the solenoid 101 and its op erationis as follows: 103 and1.02 are two contacts which are in electrical connection with wires 84and 85, leading to and from solenoid 74. When the solenoid isdeenergized, the contact 104 connects these'contacts 103 and 102 andshort-circuits the current from the solenoid 74, and when the solenoid101 is ener zed this connection is broken and the solenoid 74 sin thearmature-circuit. Therefore it for any cause the field should becomederanged and the'solenoid 101 deenergized current is cut off fromsolenoid 74 and the brake applied to a certain extent.

Having now fully described my invention, what I claim and desire toprotect by Letters Patent, is-- 1. The combination with an electricmotor, a source of current supply and motor-controlling mechanism, of abrake-wheel and brake for said motor, a brake-lever; a solenoid inseries with. the motor-armature circuit, said solenoid having a woundcore, said core being in shunt with the main, the brake-lever beingcontrolled by the said solenoid.

2. The combination with an electric motor, a source of current supplyand motor-controlling mechanism, of a brake-wheel and brake for saidmotor, .a brake-lever, a solenoid in series with the motor-armaturecircuit, said solenoid having a core, the brake-lever being controlledby the said solenoid, a switch device in the circuit to the solenoid, anelectromagnet controlling said switch device, said magnet being in thecircuit to the field of the motor.

3. The combination with an electric motor, a source of current supplyand motor controlling mechanism, of a brake-wheel and brake for saidmotor, a brake-lever, a solenoid in series with the motor-armature, saidsolenoid having a wound core, said core being in shunt with the main,the brake-lever being controlled by the said solenoid, a switch devicein the circuit tothe solenoid, an electromagnet controlling said switchdevice, said magnet being in the circuit to the field of the motor.

4. In combination with an electric motor, a source of current supply andmotor-controlling mechanism, of a brake-wheel and brake for said motor,a brake-lever, an electromagnet in shunt with the main, and connectionbetween the armature of said magnet and the brake-lever. I

5. The combination with an electric motor, asource of current supply andmotor-controlling mechanism, of a brake-wheel and brake for said motor,a brake-lever, an electromagnet in shunt with the main, and connectionbetween the armature of said magnet and'the brakelever, and a switch insaid last-mentioned circuit controlled by the motor-controllingmechanism.

6. The combination with an electric motor, a source of current supplyand motor-controlling mechanism, of a brake-wheel and brake for saidmotor, a brake-lever, an electromagnet in shunt with the main, andconnection between the armature of said magnet'and the brake-lever, aswitch in said last-mentioned 5o circuit controlled by themotor-controlling mechanism, the arrangement being such that in themovement of the motor-controlling mechanism to the center saidlast-mentioned circuit is broken prior to the breaking of the circuit tothe armature.

7. The combination with an electric motor, a source of current supplyand motor-control ling mechanism, of a brake-wheel and brake for saidmotor, a brake-lever, a solenoid in series with the motor-armaturecircuit, said solenoid having a wound core connected to the brake-lever,said core being in shunt with 'the' main, an electromagnet, inshunt-with the main, the solenoid-core being connected -to the armatureof said magnet.

8. The combination with an electric motor, a source of currentsupply-and motor-controlling mechanism, of a brake-wheel and brake forsaid motor, a brake-lever, a solenoid in series with the motor-armaturecircuit, said solenoid havin'ga wound core connected to the brake-lever,said core being in shunt with the main,- an electromagnet in shunt withthe main, the solenoid core being connected to the armature of saidmagnet, a switch in said last-mentioned circuit controlled by themotor-controlling mechanism.

9. The combination with, an electric motor, a source of, currentsupplyand motor-controlling mechanism, of a brake-wheel and brake forsaid motor, a brake-lever, .a solenoid in series with the motor-armaturecircuit, said solenoid having a wound core connected to the brake-lever,said core being in shunt with the main, an electromagnet in shunt withthe main, the solenoid-core being connected to the armature of saidmagnet, a switch in said last-me tioned circuit controlled by the'motor-controlling mechanism, the arrangement being such that in themovement of the motor-controlling mechanism to the center saidlast-mentioned circuit is broken prior to the breaking of the circuit tothe armature.

In testimony of which invention I have hereunto set my hand.

FRANK E. IIERDMAN. Witnesses:

a C. D. HOY'l,

J. J. OMEAR.

